Random, I recommend that you set up a seperate power supply. make sure you tie all the grounds together. The voltage regulator on the wiring board is only rated at 1 amp. So if you try to use it for 4 amps it is going to blow the fuse or maybe the regulator itself. I found some 3 amp 5v regulators and I use a few of those for my projects. Try not to use a regulator to it's limit. the cooler it runs the better. Heatsinks are always a good thing on regulators.